Effects of periodic hypobaric and hypoxic environment systems on glucose metabolism during endurance exercise.

Purpose: The present study aimed to determine the relationship between exercise in the periodic hypobaric hypoxic environment (PHHE) and physiological responses evaluated using an oral glucose tolerance test . Methods : This study included 13 healthy men. They provided written informed consent. All subjects performed an oral glucose tolerance test for 120 minutes and exercise tests. The exercise test started 30 minutes after oral glucose tolerance test. The exercise tests consisted of 40% maximal oxygen intake for 18 minutes, We established three experimental conditions: exercise in PHHE system (periodic), at an altitude of 750 in (fixed), and at an attitude of 0 m (control). The periodic condition varied between decreased pressure at an altitude of 1,500 m for 180 seconds and increased pressure at an altitude of 0 m for 180 seconds. Pulse rate (PR). blood pressure (BP), arterial oxygen saturation (SpO₂). and blood glucose values were measured during the oral glucose tolerance test. Heart rate (HR). SpO₂, and the rating of perceived exertion (RPE) were measured during exercise. Results and Discussion: SpO₂ was significantly lower in the periodic condition, PR, and systolic BP were significantly different among the 3 conditions. There were no significant differences in blood glucose values among the 3 conditions. During exercise, HR and RPE were not significantly different. These data suggested that glucose metabolism was not suppressed by endurance exercise in the PHHE. [ABSTRACT FROM AUTHOR]